The present invention relates to a solid-state imaging apparatus which introduces light coming from an object into the inside of the apparatus, and photoelectrically converts an image of the object with a solid-state imaging device, as well as a camera using such a solid-state imaging apparatus.
The invention also relates to a camera in which a solid-state imaging device and IC chips and other electronic parts as its peripheral circuits are formed on one surface of a circuit board, and the one surface of the circuit board is covered with a light-shielding case having an opening for allowing light coming from an object to reach the solid-state imaging device, and which camera accommodates a lens for forming an image of the object on the front face of the solid-state imaging device.
Since the solid-state imaging apparatus is required to have superior electrical and optical characteristics, the solid-state imaging device as its heart needs to be incorporated in a special package that is high in mechanical accuracy. Further, the solid-state imaging device requires a very large number of peripheral circuits. For these reasons, conventionally, IC chips and other electronic parts as peripheral circuits are mounted on a printed circuit board that is completely separate from a package accommodating a solid-state imaging device. FIG. 1 is a block diagram showing a general configuration of a solid-state imaging apparatus. In FIG. 1, symbol CCD denotes a CCD solid-state imaging device; S/H, a sample-and-hold circuit; A/D, an A/D converter, DSP, a color signal processing unit; V. DRV, a V driver; TG, a timing generator; RAM, a random access memory connected to the color signal processing unit; and CONT, a microcomputer also connected to the color signal processing unit.
In the case of a digital apparatus, examples of peripheral circuits are a sample-and-hold circuit, a timing generator, a CCD solid-state imaging device clocked driver (what is called a V-driver, for instance), an AGC (auto gain control) circuit, a clock generator (a quartz oscillator, for instance), an A/D converter, a digital camera process circuit, a D/A converter, a composite TV encoder, a digital communication peripheral circuit such as IEEE 1394, FDDI, or a fiber channel, and a DCxe2x80x94DC converter.
In the case of an analog apparatus, examples of peripheral circuits are a sample-and-hold circuit, a timing generator, a CCD solid-state imaging device clocked driver (what is called a V-driver, for instance), an AGC (auto gain control) circuit, a clock generator (a quartz oscillator, for instance), a composite TV encoder, a DCxe2x80x94DC converter, and a camera process circuit, which are part of the above peripheral circuits of a digital apparatus.
FIG. 2 shows the configuration of a conventional solid-state imaging apparatus. In FIG. 2, reference numerals 51-53 denote a CCD solid-state imaging device, a lens unit, and a solid-state-imaging-device-mounting circuit board, respectively. A flexible circuit board 54 connects the solid-state-imaging-device-mounting circuit board 53 to an IC-mounting circuit board 55 made of glass epoxy resin, for instance. Numerals 56 and 57 denote ICs mounted on the circuit board 55 and a pin jack of the circuit board 55, respectively.
The conventional solid-state imaging apparatus shown in FIG. 2 cannot fully satisfy the requirement of miniaturization. Solid-state imaging apparatuses and cameras using those are used for a wide variety of purposes. For example, while the requirement of miniaturization is not so strong in cameras for business use such as a broadcasting purpose, it is very strong in cameras for home use. As the application range expands, the requirement of price reduction becomes more important in addition to the miniaturization.
However, it is difficult to reduce the size of the solid-state imaging apparatus of FIG. 2, because it requires the solid-state-imaging-device-mounting circuit board 53, the IC-mounting circuit board 55, and the flexible circuit board 54 for connecting the circuit boards 53 and 55 and each of those circuit boards occupies a non-negligible area. Further, due to the use of many kinds of circuit boards and a number of operation steps for connecting those circuit boards, the manufacturing cost of the imaging apparatus of FIG. 2 is high and hence there is a limitation in its price reduction.
FIG. 3 shows a conventional camera. In this camera, wiring films 152 are formed on one surface of a circuit board 151, and a solid-state imaging device 153 is mounted on one of those wiring films 152. IC chips 154 as peripheral circuits of the solid-state imaging device 153 are also mounted on the wiring films 152. A lens 155 is mounted on the same surface of the circuit board 151 by means of legs 156 of the lens 155 so as to have a given positional relationship with the solid-state imaging device 153. Further, a light-shielding case 157 for shielding the solid-state imaging device 153 and the IC chips 154 from the external environment is attached to the same surface of the circuit board 151.
Reference numeral 158 denotes an opening (aperture) formed in the light-shielding case 157. Light coming from an object is passed through the opening 158 and then imaged on the front face of the solid-state imaging device 153 by the lens 155. An optical filter 159 closes the opening 158. Further, reference numeral 160 denotes bonding wires; 161, resins formed by potting to seal the IC chips 154; and 162, an adhesive for bonding the leg 156 of the lens 155 to the circuit board 151.
The camera of FIG. 3 cannot fully satisfy the requirement of miniaturization. This is because, as described above, cameras using a solid-state imaging device are used for a wide variety of purposes. For example, while the requirement of miniaturization is not so strong in cameras for business use such as a broadcasting purpose, it is very strong in cameras for home use. Further, the requirement of miniaturization is strong in many of cameras for other purposes such as a monitor camera. On the other hand, cameras using a solid-state imaging device as its heart are required to be of high performance and have many functions and, resultingly, need to incorporate many peripheral circuits. The number of peripheral circuits needed is large particularly in the case of a digital camera.
A conventional solid-state imaging apparatus to be incorporated in an electronic camera or the like has a lens for forming an image of an imaging object.
FIG. 4 is a sectional view showing a conventional solid-state imaging device. A package 201 accommodates an imaging device (CCD) 203 to protect it from the external environment. The package 201 is formed with an opening for introducing imaging light, and the opening is covered with a cover glass 205. Leads 207 for leading out an electrical signal from the imaging device 203 are extended from the package 201. The leads 207 also serve to fix the package 201 to an inner surface of a case 209.
The case 209 is mounted with a lens 211 such that its optical axis is perpendicular to the cover glass 205. The lens 211 forms an image of imaging light coming from an imaging object on the imaging face of the imaging device 203. A lens stop 213, which is provided between the lens 211 and the cover glass 205 in the case 209, limits light coming from the lens 211 to adjust the amount of light reaching the imaging device 203.
The conventional solid-state imaging apparatus 215 having the above configuration can produces an electrical signal by forming an image of imaging light that is taken through the lens 211 on the imaging face of the imaging device 3 and photoelectrically converting the image.
However, in the above conventional solid-state imaging apparatus 215, which forms an image of imaging light by using the lens 211, the lens and the lens stop 213 for light quantity adjustment are needed. This results in disadvantages, i.e., a large number of parts and a complex structure, which are obstacles to miniaturization of the apparatus.
Since the lens 211, the lens stop 213, and the imaging device 203 need to be disposed on the optical axis with high accuracy, the imaging apparatus 215 is poor in ease of assembling. Further, since these parts need to be held so as to be kept highly accurate, it is difficult to handle the imaging apparatus 215.
The above problems are also factors of increasing the manufacturing cost of the imaging apparatus 215.
The present invention has been made to solve the above problems, and an object of the invention is to reduce the size and the price of a solid-state imaging apparatus and a camera using it.
Another object of the invention is to reduce the size of a camera using a solid-state imaging device even if the camera incorporates a number of peripheral circuits.
A further object of the invention is to provide a solid-state imaging apparatus which has a smaller number of parts and a simple configuration, to thereby reduce the size, make it easier to handle the apparatus, and reduce the manufacturing cost.
According to a first aspect of the invention, there is provided a solid-state imaging apparatus comprising a solid-state imaging device; one or a plurality of bare ICs disposed on a back face or on a back face side of the solid-state imaging device, and serving as a peripheral circuit or circuits of the solid-state imaging device; and a resin for sealing the bare IC or ICs.
With this configuration, it is not necessary to mount the solid-state imaging device and the bare ICs as peripheral circuits on separate circuit boards. Further, a flexible circuit board (which is necessary in the conventional solid-state imaging apparatus shown in FIG. 2) for connecting a solid-state-imaging-device-mounting circuit board to a bare-IC-mounting circuit board is not necessary. Therefore, the size of the solid-state imaging apparatus can be reduced. Further, since it is not necessary to use many kinds of circuit boards and no circuit board for connecting circuit boards is needed, the number of parts used, their costs, and the number of assembling steps can be reduced. Therefore, the price of the solid-state-imaging apparatus can be reduced. In addition, since signal lines can be made shorter than in the conventional case, noise is less likely generated and introduced, whereby the electrical characteristics can be improved.
According to a second aspect of the invention, there is provided a solid-state imaging apparatus comprising a first package having a multilayered wiring structure; a solid-state imaging device mounted on an outer surface side of the first package; and one or a plurality of bare ICs disposed on an inner surface side of the first package and serving as a peripheral circuit or circuits of the solid-state imaging device, the one or plurality of bare ICs being connected to the solid-state imaging device via a multilayered wiring of the first package.
With this configuration, the solid-state imaging device is disposed on one side of the first package having a multilayered wiring structure and the ICs as peripheral circuits are disposed on the other side, and necessary electrical connections between the solid-state imaging device and the ICs can be established by a wiring of the first package. Therefore, the solid-state imaging device and ICs and other parts as peripheral circuits can be mounted at a higher integration density.
In a camera using the solid-state imaging apparatus according to the first or second aspect of the invention as an imaging means that is the heart of the camera, its size and price can necessarily be reduced. In addition, since signal lines can be made shorter than in the conventional case, noise is less likely generated and introduced, whereby the electrical characteristics can be improved.
According to a third aspect of the invention, there is provided a solid-state imaging apparatus comprising a circuit board; a solid-state imaging device mounted on one surface of a circuit board; a light-shielding member covering the one surface of the circuit board, the light-shielding member having an opening for allowing light coming from an object to reach the solid-state imaging device; image forming means for forming an image of the object on a front face of the solid-state imaging device; and an IC chip and/or other electronic parts as peripheral circuits of the solid-state imaging device mounted on an inner surface of the light-shielding member.
With this configuration, since IC chips and/or other electronic parts are also disposed on the inner surface of the light-shielding case, the inside space formed by the circuit board and the light-shielding case can be utilized effectively. Therefore, the camera can be miniaturized even if a number of peripheral circuits are used.
According to a fourth aspect of the invention, there is provided a solid-state imaging apparatus comprising a package structure having a dark space in itself and accommodating a solid-state imaging device in the dark space; and a pinhole for introducing imaging light into the dark space and forming an image of an imaging object on an imaging face of the solid-state imaging device; and the solid-state imaging device for photoelectrically converting the image.
With this configuration, the image formation of imaging light is enabled by the pinhole instead of a lens. Thus, a lens and a lens stop, which is conventionally required to form an image of imaging light, can be eliminated. Therefore, the number of parts can be reduced and hence the apparatus can be made simple in configuration. As a result, the solid-state imaging apparatus can be reduced in size, made easier to handle, and reduced in manufacturing cost.
The package structure may comprise a package having an opening and accommodating the solid-state imaging device; a package cover glass for closing the opening of the package; and a light-shielding member formed with the pinhole and bonded to the package cover glass. With this configuration, the pinhole can be formed by using the member for protecting the imaging device. As a result, the apparatus can be configured by a smaller number of parts and hence can be made simple in configuration.
The package structure may comprise a package; a cover case having an opening and forming the dark space together with the package; a cover glass for closing the opening of the cover case from one of an outside and an inside of the opening; and a light-shielding member formed with the pinhole, for closing the opening of the cover case from the other of the inside and the outside of the opening. With this configuration, the cover glass and the light-shielding member can be formed as separate members. As a result, the degree of freedom in selecting their shapes and materials can be increased.